Proposal for construction of traffic connection route through Da Nang airport

The Department of Construction recently reported on a proposal to build an east-west traffic connection route through Da Nang airport. According to the department's proposal, to build a tunnel through the airport, the section outside the operating runway will be constructed with closed and open tunnels using the open excavation method; the section under the operating runway has two options: using the Pipe Roof method and the TBM method.

Da Nang Airport. Photo: THANH LAN

The Department of Construction proposed to apply the Pipe Roof method for the section under the runway, because the tunnel is shallow, easily connected to outside traffic and many similar projects in the world have applied this method. This method is conveniently applied to underpasses, construction in areas with heavy traffic or limited interruptions or where settlement needs to be minimized during construction.

This method involves the construction of temporary structures using interlocking steel pipes, installed by micro-tunnel or underground jacking, to form a temporary soil support system, and then the permanent structure can be built inside. The advantage of the Pipe Roof method is that steel pipe diameters ranging from 318.4~1219.2 are used. The small diameter makes shallow tunneling possible; the variety of pipe roof arrangements allows for the construction of various excavation profiles; and it is cheaper and faster than the TBM tunneling method.

The highlight of the two proposed technologies above is to build tunnels through roads and land (airports) while the above is still operating normally. On the Pipe Roof side, pipes are used to penetrate around the perimeter of the tunnel, then dig and use a frame system to support the pipes and build the tunnel shell, then continue in that cycle moving forward (can also be divided into sections to do if the route is long).

For the East-West traffic connection project through Da Nang airport, the Department of Construction proposed a tunnel line of more than 2.9km long, including 2 open tunnel sections with a total length of 570m, 3 box tunnel sections with a total length of 1,450m and a tunnel through the existing runway of 900m. There are 2 proposed options. Option 1 is a subway line (MRT) running with the road; option 2 is an MRT line not running with the road.

According to the analysis, option 1 has high technical difficulty, cost about 10,000 billion VND, average safety/operation level, difficulty in expanding MRT, high level of suitability for Da Nang International Airport infrastructure. Meanwhile, option 2 has lower technical difficulty, cost about 7,500 billion VND, high safety/operation level, easy to expand MRT, average level of suitability for Da Nang International Airport infrastructure.

With the MRT system combined with the road tunnel, the integration of the MRT and road tunnel in the same tunnel structure helps reduce the occupied area, especially in the airport area where land is often limited. The cost of tunnel excavation and infrastructure construction is also reduced because it only needs to be constructed once; at the same time, only one tunnel is needed instead of two, which helps limit the impact on airport operations on the ground such as runways and terminals. In addition, passengers from the airport can easily switch between MRT and road vehicles in the same area, improving the travel experience.

For the MRT system with separate road tunnels, the MRT and road tunnels operate separately, so a problem in one system does not directly affect the other, ensuring continuity and stability. Repairs, expansions or renovations to one system can be carried out without interfering with the other, minimizing disruptions. In addition, each tunnel serves only one type of vehicle, so technical requirements (ventilation, load, safety) are optimized separately, reducing complexity in construction. The location or route of each tunnel can be adjusted to suit the specific needs of the airport without being constrained by the other system.

The Department of Construction recommends that for the tunnel route through the airport, it is not advisable to combine the MRT route and the road route. The reason is that the technical standards of the MRT and the road are different, so the combination will be quite forced. At the same time, the investment progress of the MRT route has not been determined, so with rapid changes in technology, the route direction and technology will be selected at the time of investment. However, with actual conditions such as Da Nang airport being planned for expansion, the MRT route option also needs to be studied soon.

Source: https://baodanang.vn/kinhte/202504/de-xuat-phuong-an-xay-dung-tuyen-ket-noi-giao-thong-qua-san-bay-da-nang-4005621/